I was browsing through Play comments for Boxer, this new -- and very nice -- email app.
This caught my attention:
$20 seriously?? You say Microsoft charge to use active sync, that's how you justify $10 extra. Then explain how an app like Aqua mail don't charge for exchange accounts and the cost is a fraction of your price? I thought id try something new but you've convinced me that Aqua mail was a better purchase option, thanks.
This is not meant to bash another -- great looking and nicely featured -- mail app, but it just shows that ...
... choosing EWS vs. ActiveSync is a lose-lose proposition. There is no winning option here.
Go with EWS, and you may find it disabled on some servers, or enabled and unable to send, or other issues.
Go with ActiveSync, and make potential users angry at having to cover ActiveSync licensing costs... And the more complicated product structure (e.g. Boxer free, Boxer Pro, Boxer Pro Plus... complaints about that too).
Again, not trying to say anything bad about other people's -- great -- work.
Just a very specific point about Exchange connectivity.